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de Pasquale F, Spadone S, Betti V, Corbetta M, Della Penna S. Temporal modes of hub synchronization at rest. Neuroimage 2021; 235:118005. [PMID: 33819608 DOI: 10.1016/j.neuroimage.2021.118005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 10/21/2022] Open
Abstract
The brain is a dynamic system that generates a broad repertoire of perceptual, motor, and cognitive states by the integration and segregation of different functional domains represented in large-scale brain networks. However, the fundamental mechanisms underlying brain network integration remain elusive. Here, for the first time to our knowledge, we found that in the resting state the brain visits few synchronization modes defined as clusters of temporally aligned functional hubs. These modes alternate over time and their probability of switching leads to specific temporal loops among them. Notably, although each mode involves a small set of nodes, the brain integration seems highly vulnerable to a simulated attack on this temporal synchronization mechanism. In line with the hypothesis that the resting state represents a prior sculpted by the task activity, the observed synchronization modes might be interpreted as a temporal brain template needed to respond to task/environmental demands .
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Affiliation(s)
- F de Pasquale
- Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
| | - S Spadone
- Department of Neuroscience, Imaging and Clinical Sciences, and Institute for Advanced Biomedical Technologies, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
| | - V Betti
- Department of Psychology, Sapienza University of Rome, 00185, Rome, Italy; IRCCS Fondazione Santa Lucia, 00142, Rome, Italy
| | - M Corbetta
- Department of Neuroscience and Padova Neuroscience Center (PNC), University of Padua, Padua, Italy; Venetian Institute of Molecular Medicine (VIMM), Padua, Italy; Department of Neurology, Radiology, and Neuroscience, Washington University St. Louis
| | - S Della Penna
- Department of Neuroscience, Imaging and Clinical Sciences, and Institute for Advanced Biomedical Technologies, "G. d'Annunzio" University of Chieti-Pescara, Chieti, Italy
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Abstract
Spontaneous brain activity is spatially and temporally organized in the absence of any stimulation or task in networks of cortical and subcortical regions that appear largely segregated when imaged at slow temporal resolution with functional magnetic resonance imaging (fMRI). When imaged at high temporal resolution with magneto-encephalography (MEG), these resting-state networks (RSNs) show correlated fluctuations of band-limited power in the beta frequency band (14-25 Hz) that alternate between epochs of strong and weak internal coupling. This study presents 2 novel findings on the fundamental issue of how different brain regions or networks interact in the resting state. First, we demonstrate the existence of multiple dynamic hubs that allow for across-network coupling. Second, dynamic network coupling and related variations in hub centrality correspond to increased global efficiency. These findings suggest that the dynamic organization of across-network interactions represents a property of the brain aimed at optimizing the efficiency of communication between distinct functional domains (memory, sensory-attention, motor). They also support the hypothesis of a dynamic core network model in which a set of network hubs alternating over time ensure efficient global communication in the whole brain.
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Affiliation(s)
- F de Pasquale
- Institute for Advanced Biomedical Technologies, Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University, Chieti, Italy
| | - S Della Penna
- Institute for Advanced Biomedical Technologies, Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University, Chieti, Italy
| | - O Sporns
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - G L Romani
- Institute for Advanced Biomedical Technologies, Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio" University, Chieti, Italy
| | - M Corbetta
- Departments of Neurology, Radiology, Anatomy and Neurobiology, Washington University School of Medicine, Saint Louis, MO, USA ITAB, University of Chieti, Chieti, Italy
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Sanchez-Castaneda C, de Pasquale F, Caravasso C, Sabatini U, Squitieri F. E22 Resting State Fmri And Grey Matter Volume In Huntington Disease. Journal of Neurology, Neurosurgery & Psychiatry 2014. [DOI: 10.1136/jnnp-2014-309032.125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Formisano R, Catani S, Caravasso CF, D'Ippolito M, de Pasquale F, Sabatini U. Islands of consciousness in vegetative state or functional locked-in syndrome? J Neurol Sci 2013. [DOI: 10.1016/j.jns.2013.07.1945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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de Pasquale F, Pennal SD, Mantini D, Marzetti L, Lewis C, Pizzella V, Snyder AZ, Romani GL, Corbetta M. Temporal dynamics of spontaneous activity in brain networks. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)70019-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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de Pasquale F, Del Gratta C, Romani G. Empirical Markov Chain Monte Carlo Bayesian analysis of fMRI data. Neuroimage 2008; 42:99-111. [DOI: 10.1016/j.neuroimage.2008.04.235] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 04/16/2008] [Accepted: 04/17/2008] [Indexed: 11/26/2022] Open
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de Pasquale F, Tartaglia P, Tombesi P. Stochastic approach to chemical instabilities: Anomalous fluctuation and transient behaviour. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/bf02772919] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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de Pasquale F, Barone P, Sebastiani G, d'Errico F, Egger E, Luciani AM, Pacilio M, Guidoni L, Viti V. Ion diffusion modelling of Fricke-agarose dosemeter gels. Radiat Prot Dosimetry 2006; 120:151-4. [PMID: 16644939 DOI: 10.1093/rpd/nci683] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In Fricke-agarose gels, an accurate determination of the spatial dose distribution is hindered by the diffusion of ferric ions. In this work, a model was developed to describe the diffusion process within gel samples of finite length and, thus, permit the reconstruction of the initial spatial distribution of the ferric ions. The temporal evolution of the ion concentration as a function of the initial concentration is derived by solving Fick's second law of diffusion in two dimensions with boundary reflections. The model was applied to magnetic resonance imaging data acquired at high spatial resolution (0.3 mm) and was found to describe accurately the observed diffusion effects.
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Affiliation(s)
- F de Pasquale
- Istituto per le Applicazioni del Calcolo, CNR, viale del Policlinico 137, 00161 Rome, Italy
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Viti V, d'Errico F, Pacilio M, Luciani AM, Palma A, Grande S, Ranghiasci C, Adorante N, Guidoni L, Rosi A, Ranade M, de Pasquale F, Barone P, Sebastiani G. Optical imaging of dose distributions in Fricke gels. Radiat Prot Dosimetry 2006; 120:148-50. [PMID: 16614085 DOI: 10.1093/rpd/ncj005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Ferrous-sulphate infused gels, or 'Fricke gels', encounter great interest in the field of radiation dosimetry, due to their potential for 3D radiation dose mapping. Typically, magnetic resonance (MR) relaxation rates are determined in these systems in order to derive the absorbed dose. However, when large concentration gradients are present, diffusion effects before and during the MR imaging may not be negligible. In these cases, optical techniques may represent a viable alternative. This paper describes research aimed at measuring 3D dose distributions in a Fricke-xylenol orange gel by measuring optical density with a CCD camera. This method is inexpensive and fast. A series of early experiments is described, in which optical density profiles were measured with a commercial microdensitometer for film dosimetry. The light box of the device was modified to work at 567 nm, close to the maximum absorbance of the ferric ion-xylenol orange complex. Under these conditions, the gel shows linearity with dose and high sensitivity.
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Affiliation(s)
- V Viti
- Yale University School of Medicine, New Haven, CT 06510, USA.
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Abstract
We present a model of quantum teleportation protocol based on a double quantum dot array. The unknown qubit is encoded using a pair of quantum dots, with one excess electron, coupled by tunneling. It is shown how to create a maximally entangled state using an adiabatically increasing Coulomb repulsion between different dot pairs. This entangled state is exploited to perform teleportation again using an adiabatic coupling between itself and the incoming unknown state. Finally, a sudden separation of Bob's qubit allows a time evolution of Alice's, which amounts to a modified version of standard Bell measurement. A transmission over a long distance could be obtained by considering the entangled state of a chain of N coupled double quantum dots. The system is shown to be increasingly robust with N against decoherence due to phonons.
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Affiliation(s)
- F de Pasquale
- INFM Center for Statistical Mechanics and Complexity, Università di Roma La Sapienza, Piazzale A. Moro 2, 00185 Rome, Italy.
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de Pasquale F, Luciani AM, Pacilio M, Guidoni L, Viti V, d'Errico F, Barone P, Sebastiani G. Dose reconstruction in irradiated Fricke-agarose gels by means of MRI and optical techniques: 2D modelling of diffusion of ferric ions. Radiat Prot Dosimetry 2002; 99:363-364. [PMID: 12194325 DOI: 10.1093/oxfordjournals.rpd.a006803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Fricke-agarose gels have elicited much interest in the field of radiation dosimetry, as tissue-equivalent dosemeters. magnetic resonance (MR) relaxation rates are measured for dose reconstruction. A major problem of Fricke-agarose gels is the diffusion of the ferric ions formed after irradiation. Knowledge of the diffusion coefficient of ferric ions may be necessary. Xylene orange, a dye that specifically chelates ferric ions, was added to the Fricke gel system to reduce ion diffusion and, as the binding gives a coloured complex, to allow optical detection of ferric ions. Diffusion of ferric ions in two dimensions and time evolution of ion concentration were evaluated. MR images were obtained at different times after irradiation. Ferric ion distribution, the corresponding images and the doses at different times after irradiation were reconstructed taking into account the calculated diffusion coefficients. Diffusion was then estimated by means of two different optical methods. The agreement obtained supports the reliability of the MRI method and of the model.
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de Pasquale F, Sebastiani G, Egger E, Guidoni L, Luciani AM, Marzola P, Manfredi R, Pacilio M, Piermattei A, Viti V, Barone P. Bayesian estimation of relaxation times T(1) in MR images of irradiated Fricke-agarose gels. Magn Reson Imaging 2000; 18:721-31. [PMID: 10930782 DOI: 10.1016/s0730-725x(00)00149-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The authors present a novel method for processing T(1)-weighted images acquired with Inversion-Recovery (IR) sequence. The method, developed within the Bayesian framework, takes into account a priori knowledge about the spatial regularity of the parameters to be estimated. Inference is drawn by means of Markov Chains Monte Carlo algorithms. The method has been applied to the processing of IR images from irradiated Fricke-agarose gels, proposed in the past as relative dosimeter to verify radiotherapeutic treatment planning systems. Comparison with results obtained from a standard approach shows that signal-to noise ratio (SNR) is strongly enhanced when the estimation of the longitudinal relaxation rate (R1) is performed with the newly proposed statistical approach. Furthermore, the method allows the use of more complex models of the signal. Finally, an appreciable reduction of total acquisition time can be obtained due to the possibility of using a reduced number of images. The method can also be applied to T(1) mapping of other systems.
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Affiliation(s)
- F de Pasquale
- Istituto per le Applicazioni del Calcolo, Consiglio Nazionale delle Ricerche, viale del Policlinico 137, Rome, Italy.
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Hernández-Figueroa HE, Pasquale FD, Ettinger RD, Fernéndez FA, Davies JB. Controlled spatial bright soliton emission from a nonlinear waveguide. Opt Lett 1994; 19:326-328. [PMID: 19829631 DOI: 10.1364/ol.19.000326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An efficient technique for controlling the spatial bright soliton emission from a nonlinear waveguide is demonstrated numerically for what is to our knowledge the first time. The principle of this technique is based on the addition of a weak antisymmetric signal as a probe, the control parameters being the amplitude and the phase of the probe. A novel nonlinear device, the three-waveguide soliton coupler, is introduced and discussed as an application.
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